If your cordless lawn mower hits a rock or other hard object, there are a few steps you should take:

Inspect the blade: Once the mower is stopped, inspect the blade for damage.  If the blade is bent or damaged, it will need to be replaced before you can use the mower again.

Check for other damage: In addition to the blade, check the underside of the mower for any other signs of damage.  This can include bent or damaged deck components or loose bolts or screws.

Clear any debris: If the rock or other object is still stuck in the blade or deck, carefully remove it using a pair of pliers or another tool.  Be sure to wear gloves and exercise caution when doing this.

Test the mower: After completing these steps, test the mower to ensure that it is working properly.  If you notice any unusual noises or vibrations, or if the mower is not cutting properly, turn it off and inspect it again.

If you're unsure about how to inspect or repair your cordless lawn mower after hitting a rock or other hard object, it may be best to take it to a professional for service.  They can help you diagnose and address any issues and ensure that your mower is safe to use.https://www.airbike.top/products/airbike-brush-cutter-weed-wacker-weed-eater-edger-lawn-tool-powerful-lightweight-for-lawn-yard-garden-shrub-trimming-and-pruning?data_from=app_productrec